Batteries are easily affected by temperature, batteries degrade at high temperatures, and battery performance cannot be realized at low temperatures. In the case of a module formed by combining multiple battery cells, due to self-generated heat from a battery during use, the degree of heat dissipation differs in accordance with position of the battery cell in the module, and a deviation occurs in the temperature distribution of the module. The battery is cooled by cooling air flow to decrease the deviation of the temperature distribution, and the deviation of the temperature distribution of the module is reduced.
A power supply device disclosed in Patent Literature 1 decreases the deviation of the temperature distribution by cooling the battery cells by blowing a coolant gas through a cooling gap from a side surface of a battery block, and by providing a temperature equalization plate partially blocking an opening of the cooling gap such that an amount of coolant gas flowing in the cooling gap decreases with increasingly far position of the battery cell in an upstream direction of the flow of the coolant gas.